The present invention relates to air conditioning systems, including those mounted on vehicle rooftops (i.e., buses, temperature-controlled delivery vehicles, etc.). There is an inherent need for manufacturers of these types of air conditioning systems to tailor the various system components to meet the particular specifications of a variety of vehicles. Thus, the number of different parts among unique systems, even though the majority of the unique systems are quite similar, can be rather high in order to meet all of the various customer needs. One partial solution to this problem, found in U.S. Pat. No. 7,051,544, is to manufacture only one type of air conditioning module and provide a plurality of the modules in a number configured to meet the specified cooling need of each different vehicle. However, this results in an extreme duplication of parts for a large vehicle (i.e., when 4, 6, or 8 modules, each containing all the basic components of a self-contained air conditioning system, are required for a single vehicle). Obviously, this significantly increases the assembly effort, and furthermore, presents greater statistical opportunity for failure on a given vehicle.
In addition, it may be necessary to provide not only differently-sized components (to meet a specified cooling need), but wholly different types of modules within air conditioning systems to meet the growing needs of vehicle manufacturers. For example, it is common for the refrigerant in a rooftop air conditioning system to be compressed by a compressor located in the vehicle's engine compartment and driven directly from the engine. However, it may be desirable or necessary to position the compressor directly in the rooftop air conditioning unit in some vehicles. Furthermore, it may be desirable or necessary in some vehicles to incorporate electrical power conversion components into the air conditioning system to convert AC power directly from an alternator into usable DC power for running the electrical components of the air conditioning system. A small cooling system may also be provided to cool the electrical power conversion components. Yet another common variation involves providing a separately-controlled secondary air conditioning system for a dedicated portion of the vehicle (e.g., a cab or driver's quarters versus the primary system that is used for a cargo or passenger area). Of course, one universal frame and housing structure could be designed to be capable of receiving all of the possible hardware for all of the various permutations of air conditioning systems, but this results in a costly waste of materials and space in most if not all of the realistic air conditioning system configurations to be produced. Rather, the conventional approach has been to produce standalone designs for each different type of air conditioning system in an attempt to make the most efficient use of materials. However, this results in each different type of air conditioning system being very unique from the others (e.g., alternate routing of fluid tubing, individualized frames and covers configured for a particular group of components). Examples of these are shown in FIGS. 1A-1D.
FIG. 1A illustrates a first air conditioning system 20A including a frame that supports a condenser, an evaporator coil, a heater, and a blower, some or all of which are at least partially enclosed by a plurality of covers 24A. The air conditioning system 20A is configured to be coupled with a remote compressor (e.g., a compressor located in the engine bay of a vehicle and driven by the engine), but is otherwise provided with a complete internal closed-loop fluid circuit.
FIG. 1B illustrates a second air conditioning system 20B including a frame that supports a condenser, an evaporator coil, a heater, and a blower, some or all of which are at least partially enclosed by a plurality of covers 24B. The air conditioning system 20B further includes an electrically-driven hermetic compressor, which is on-board as opposed to the air conditioning system 20A of FIG. 1A which operates with a remote compressor. Therefore, the air conditioning system 20B of FIG. 1B is provided with a complete internal closed-loop fluid circuit. Although the system 20B of FIG. 1B may be identical in cooling capacity to the system 20A of FIG. 1A, at least the respective frames and the respective covers 24A, 24B are required to be unique from each other to accommodate the alternate configurations.
FIG. 1C illustrates a third air conditioning system 20C including a frame that supports a condenser, an evaporator coil, a heater, and a blower, some or all of which are at least partially enclosed by a plurality of covers 24C. Like the air conditioning system 20B of FIG. 1B, the system 20C of FIG. 1C includes an on-board electrically-driven hermetic compressor and a complete internal closed-loop fluid circuit. However, the system 20C further includes a power conversion unit configured to receive a variable AC input from an alternator (i.e., vehicle engine-driven alternator) and provide a predetermined DC output to the on-board compressor. Although the system 20C of FIG. 1C may be identical in cooling capacity to the system(s) 20A, 20B of FIGS. 1A and 1B, at least the respective frames and the respective covers 24A, 24B, 24C are required to be unique from each other to accommodate the alternate configurations.
FIG. 1D illustrates a fourth air conditioning system 20D including a frame that supports a condenser, an evaporator coil, a heater, and a blower, some or all of which are at least partially enclosed by a plurality of covers 24D. Like the system 20A of FIG. 1A, the system 20D of FIG. 1D is configured to be coupled with a remote compressor (e.g., a compressor located in the engine bay of a vehicle and driven by the engine), but is otherwise provided with a complete internal closed-loop fluid circuit. Unlike the system 20A of FIG. 1A, the system 20D of FIG. 1D further includes a secondary air conditioning system 28D with a secondary cooling coil, a secondary heater, and a secondary blower. The secondary air conditioning system 28D is configured to provide dedicated temperature control to a designated vehicle portion, such as a driver's quarters or “cab”. Although the system 20D of FIG. 1D may be identical in cooling capacity to the system 20A of FIG. 1A, at least the respective frames and the respective covers 24A, 24D are required to be unique from each other to accommodate the alternate configurations. Thus, a constant struggle exists for efficiently designing any type of “universal” air conditioning system.